1. Field of the Invention
The present invention relates to an image processing apparatus, a non-transitory computer-readable medium storing a computer program, and an image processing method, for performing white balance correction of a moving image.
2. Description of the Related Art
Conventionally, auto white balance (AWB) processing for automatically correcting a white balance (WB) of a moving image has been performed. If an optimal WB gain is calculated in a unit of a frame and AWB processing is performed using the calculated WB gain, the color and brightness of an image change for each frame, and such change of the color and brightness is perceived as flickering, which makes the image difficult to see. In order to address such a problem, in the AWB processing, WB correction is performed using a hysteresis gain (WB gain having a value whose up-and-down fluctuation for each frame is suppressed) calculated based on WB gains of a plurality of frames.
Japanese Patent Application Laid-Open Publication No. 2003-348601, for example, discloses an auto white balance control method and an electronic camera in which after AWB processing is performed at the start of moving image photographing in a moving image photographing mode, a WB gain is fixed without executing periodic AWB processing during the moving image photographing, and an AE evaluation value is monitored and when the AE evaluation value fluctuates by a prescribed value or more, fixing of the WB gain is automatically released and the AWB processing is executed again. Such a technique is capable of reducing the processing load of a control section, which enables the cost of electronic cameras and the like to be reduced.
Although the technique disclosed in Japanese Patent Application Laid-Open Publication No. 2003-348601 is not intended to reduce flickering, the technique is expected to exhibit an effect of suppressing the flickering to be generated due to the fluctuation of the WB gain value for each frame. Furthermore, the technique is capable of setting a white balance suitable for each scene by automatically releasing the fixing of the WB gain depending on a change of a scene.